anticoagulants service Flashcards
name example oral anticoagulant - direct acting oral anticoagulant
Dabigatran
Apixaban
Rivaroxaban
Edoxaban
name examples of vitamin K antagonist
Warfarin
Phenindione
Acenocoumarol
name some injectable anticoagulant - lmwh
Unfractionated heparin Enoxaparin - LMWH Tinzaparin - LMWH Dalteparin -LWMH Fondaparinux sodium
mechanism of action of warfarin
Vitamin K antagonist/vitamin K epoxide reductase inhibition
Acts on multiple coagulation factors
mechanism of action of DOAC
Dabigatran is a direct thrombin inhibitor.
Other DOACs act on Factor XA
Similar efficacy to warfarin
mechanism of action of LMWHs/fondaparinux?
LMWHs act on Xa and IIa
Fondaparinux on Xa ONLY
why are anticoagulants prescribed?
PROPHYLAXIS / PREVENTION of:
Deep vein thrombosis (DVT) Pulmonary embolism (PE) Mural thrombus (often in ventricle after MI or can be peripheral)
Treatment of acute ST-segment elevation myocardial infarction (STEMI) and Non-ST-segment-elevation myocardial infarction (NON-STEMI), unstable coronary artery disease (LMWH ONLY)
when is warfarin/ LMWH given
Atrial Fibrillation (AF) (all types)
after insertion of prosthetic heart valves
after surgery
clotting disorders (e.g. thrombophilia)
when are DOAC given?
after hip or knee replacement surgery
patients with non-valvular AF with one or more other risk factors such as previous stroke, diabetes mellitus
what are the advantage and disadvantage of LMWH (low molecular weight heparin)
A: rapid onset of action
predictable - dose-dependent plasma level
long half life
in convenience - pre filled syringes
D:
S/C administration: not liked by patients / compliance issues/difficulty with technique/ need for district nurse support/local side effects/disposal of syringes
Complex dosing regimes: depend on patient weight and indication, some expressed as units, some as mg-difficult to prescribe and dispense
Expensive: Clexane (enoxaparin) 40mg/0.4ml solution for injection pre-filled syringes 10=£30.27 1 year=£1105
what are the advantage and disadvantage of warfarin
A:
Cheap: 5mg 28=£0.70, 3mg=£0.67 1year ≈£20
Requires INR monitoring ( ≈£200 p/a)
INR monitoring demonstrates efficacy
> 60 years of use
Useful in most situations where oral anticoagulant needed
Specific reversal agent- vitamin K
Tailored to the reason for use and to patient (target INR)
Slow to clear – one missed dose and patient still anticoagulated
Dis:
INR control affected by diet, alcohol, weight loss/gain, illness, medication etc
Wide range of doses
Slow to stabilise INR
Difficult to stabilise in some patients
what are the advantage and disadvantage of DOACS
A: No monitoring required Tailored to the reason for use Few drug/food interactions Fast time to onset
D:
Expensive: Apixaban 5mg 56=£53.20 1 year = £638.40
Rapid clearance – one missed dose and effects lost
Less experience
Limited product licences
Specific reversal agent for dabigatran Praxbind®(idarucizumab, £2400 per dose) but not others
No test of efficacy
Dabigatran unstable in MDS trays and cannot be crushed (unlicenced use of other DOACs / warfarin)
what is Warfarin-International Normalized Ratio (INR)
An INR test measures how long it takes blood to clot
It is the ratio of the Prothrombin Time (PT) of the subject compared to a normal control
Normal clotting time is 10-14 seconds, with an INR of 1
Time in Therapeutic Range (TTR) = % of timeframe when INR in range (aim>65%)
INR targets
depending on how high the risk is to get thrombosis - you are given a different INR target -
higher risk = higher target
low risk = lower target - target = 2.5 and range is 2-3
the people effected:
Atrial Fibrillation (AF)
Venous thromboembolism (VTE)
Bioprosthetic heart valve in mitral position
Bio prosthetic heart valve with additional prothrombotic risk factors e.g. AF
higher risk for thrombus - if they have mechanical aortic valve
target of 3
range 2.5-3.5
highest risk of thrombus -
Recurrent VTE whilst on anticoagulants and control within target range
High risk mechanical prosthetic heart valves e.g. mitral valves
Mechanical prosthetic heart valves with additional prothrombotic risk factors e.g. AF
target of 3.5
range- 3-4
INR targets
depending on how high the risk is to get thrombosis - you are given a different INR target -
higher risk = higher target
low risk = lower target - target = 2.5 and range is 2-3
the people effected:
Atrial Fibrillation (AF)
Venous thromboembolism (VTE)
Bioprosthetic heart valve in mitral position
Bio prosthetic heart valve with additional prothrombotic risk factors e.g. AF
higher risk for thrombus - if they have mechanical aortic valve
target of 3
range 2.5-3.5
highest risk of thrombus -
Recurrent VTE whilst on anticoagulants and control within target range
High risk mechanical prosthetic heart valves e.g. mitral valves
Mechanical prosthetic heart valves with additional prothrombotic risk factors e.g. AF
target of 3.5
range- 3-4
Aims of pharmacist led anticoagulation services
Offer standardised, clinically effective and safe monitoring and management of patients on anticoagulants in the community
Ensure patients have access to a convenient, local service and reduced waiting times
Provide warfarin patients with INR tests using ‘Point of Care Testing’ device-instant results and less invasive fingerprick test compared to phlebotomy
Improve patient understanding of and compliance with their treatment by providing ongoing education, support and a one-stop service
what service is given to patients on warfarin
Advice on administration, side effects, etc
Testing of INR using Point of Care Testing (POCT) equipment e.g. Coaguchek (Roche®)
Management of warfarin dose
Referral to anticoagulation clinic/ GP if outside scope of POCT service
Supplying warfarin on Patient Group Direction (PGD)/ Patient Specific Direction
(PSD) or on prescription from GP
‘Bridging’ service between being on LMWH during hospital admission/ resuming oral warfarin on discharge until patient INR in range
Visiting housebound patients and INR testing in patients’ homes
Supporting self testing patients
what is the services provided for patients on DOAC
Advice on adherence, side effects, lifestyle impact of anticoagulants, et
Which warfarin patients use the pharmacy led service?
Referred by GPs or hospital anticoagulation team
Adults
Usually stable long term patients
Usually complex high risk patients excluded, e.g. pregnancy, GI bleed in the last 6 months (medical records not available to pharmacists)
Patient choice
Pharmacy led anticoagulation services
Anticoagulation service requires good communication between stakeholders
who are the stakeholders
= GP
=Anticoagulation pharmacist (Fingerprick blood testing)
=Hospital anticoagulation Clinic (Venous blood testing)
Pharmacist Led service
After receiving a referral:
Book patient into the pharmacist led anticoagulation clinic
At the first appointment:
Introduce self, check patient ID, add patient details to INRStar/DAWN
Check informed consent to pharmacist led service
Discussion tailored to patient’s needs and level of understanding (Accessible Information Standard 2016) on:
Yellow book, warfarin tablets, importance of managing blood INR level within their therapeutic range
Risks of not doing so
Factors affecting INR e.g. drug interactions, illness, diet, alcohol
Hospital admissions, dental or surgical treatment
Side effects and how to deal with bleeding episodes
Who to contact with concerns or queries
Summarise important points
Document everything
how to carry out INR test
Clean area with alcohol wipes
Wash hands, put on gloves
Get patient to wash hands with warm water and dry
Take capillary blood sample –use disposable lancet
Analyse sample using Coaguchek XS Pro II
Clean area and equipment
Input INR data into INRStar/DAWN – amend dose of warfarin-use program/ knowledge/ judgement
Next test date calculated by INRStar/DAWN (or work out from patient risk factors/ change to INR). Inform patient
Copy of INRStar/DAWN printout to patient and update yellow book
Inform GP / anticoagulant clinic of result (if required
what can be the causes of INR being out of therapeutic range
Missed tablets?
Been unwell (diarrhoea, a stay in hospital, tests or interventions)?
Had lifestyle changes that affect daily routine?
Changed or started any prescription or OTC medicine, vitamins/ herbal remedies?
Made any major dietary / alcohol changes / celebration e.g.
Crash diets
Binge eating
Marked changes in alcohol consumption
Been on holiday?
Had any kind of trauma / injury?
Had any unexpected bruising or bleeding, e.g
Prolonged bleeding from cuts
Nose bleeds
Bleeding gums
Red or dark brown urine
Red or black stools (black tar-like stools)
For women, increased bleeding during periods (or any other vaginal bleeding)
